This is a proposal to investigate the advantages of a new 2048x2048 pixel CCD type solid state image sensor for X-ray diffraction applications on biological macromolecules. In the proposed experiments the CCD will be fiber optically coupled directly to an X-ray sensitive phosphor screen, eliminating the image intensifier normally employed in such X-ray diffraction imaging equipment. This results in a substantial improvement in spatial resolution and dynamic range. Arrangements have been made to test the CCD imaging system in Prof. Sol Gruner's X-ray diffraction laboratory in Princeton University, Department of Physics. Princeton Scientific Instruments has the 2048x2048 pixel CCD camera system which would be used for these experiments. This grant would support designing and building the fixture for mounting the CCD and fiber optics phosphor screen together and conducting the experiments and analyzing the data. The proposed Phase I program is a cost effective way to investigate the advantages of these new image sensors to X-ray diffraction related research. The high resolution and wide dynamic range of this CCD imaging system is particularly well matched to the problem of X-ray Laue diffraction from protein crystals using synchrotron generated polychromatic X-rays and protein diffraction from large unit cells, a Phase II project.